A knock-in allele of Hand2 expressing Dre recombinase

HAND2 is a basic helix–loop–helix transcription factor with diverse functions during development. To facilitate the investigation of genetic and functional diversity among Hand2-expressing cells in the mouse, we have generated Hand2^Dre, a knock-in allele expressing Dre recombinase. To avoid disrupting Hand2 function, the Dre cDNA is inserted at the 3′ end of the Hand2 coding sequence following a viral 2A peptide. Hand2^Dre homozygotes can therefore be used in complex crosses to increase the proportion of useful genotypes among offspring. Dre expression in mid-gestation Hand2^Dre embryos is indistinguishable from wild-type Hand2 expression, and Hand^Dre efficiently recombines rox target sites in vivo. In combination with existing Cre and Flp mouse lines, Hand2^Dre will therefore extend the ability to perform genetic intersectional labeling, fate mapping, and functional manipulation of subpopulations of cells characterized by developmental expression of Hand2.